A micro-flow-batch analyzer with solenoid micro-pumps for the photometric determination of iodate in table salt

Abstract

In this study, a micro-flow-batch analyzer (μFBA) with solenoid micro-pumps for the photometric determination of iodate in table salt is described. The method is based on the reaction of iodate with iodide to form molecular iodine followed by the reaction with N,N-diethyl-p-phenylenediamine (DPD). The analytical signal was measured at 520nm using a green LED integrated into the μFBA built in the urethane–acrylate resin. The analytical curve for iodate was linear in the range of 0.01–10.0mgL−1 with a correlation coefficient of 0.997. The limit of detection and relative standard deviation were estimated at 0.004mgL−1 and<1.5% (n=3), respectively. The accuracy was assessed through recovery test (97.6–103.5%) and independent analysis by a conventional titrimetric method. Comparing this technique with the conventional method, no statistically significant differences were observed when applying the paired t–test at a 95% confidence level. The proposed microsystem using solenoid micro-pumps presented satisfactory robustness and high sampling rate (170h−1), with a low reagents consumption and a low cost to build the device. The proposed microsystem is a new alternative for automatic determination of iodate in table salt, comparing satisfactory to the recently flow system.